Re: MaxTransferLength

[Nicolas D <nd@saitis.net>]

Hello,

On Tue, Apr 24, 2018 at 07:53:53AM -0500, Bryant G. Ly wrote:
> 
> On 4/24/18 7:38 AM, Hannes Reinecke wrote:
> 
> >'pscsi' is the SCSI pass-through, so it'll be presenting the
> >values from the underlying device; I doubt you can change that.

I have tried to tweak /sys/block/sr0/queue/max_sectors_kb but with no
luck (sr0 is the backend exported) Can you tell me if targetcli use this
value? And if yes, when is it taken into account? (on backend creation?
when the initiator connects? sometime else?)

> >What you could try is to mount the DVD, and export the mountpoint
> >via the file backend; that way you should be able to tweak the
> >parameters.

I forgot to say that the goal is to play dvd/bd video disks and that I
need the pass-through for all the special commands needed to authenticate
the drive etc. So using the file backend does not seem to be an option.

> Adding to what Hannes is saying, if you need true dvd/cd emulation you can
> use file optical media backstore via user:fbo from tcmu-runner.

Does the user:fbo handle the necessary special command for video dvd/bd?

In that story I had exactly the same extremely slow behaviour described
in this old post before I could limit the maximum transfer size:
https://www.spinics.net/lists/target-devel/msg06277.html

Ramin Mahmoodi, do you still read target-devel?

Nicolas